I recently discovered Bitcoins (too late ) and I started mining with my GTX 580. No need to say that it is kind of useless for this purpose. Now I was thinking about building a rig exclusively for mining. The reason I seek your help is, that all the hardware related information found on the web seems either slighlty outdated (mid 2011) or very vague. I am no expert on hardware, so I would be glad about any suggestions. I'd like the rig to pay for itself and after a year or so make some profit (even with the high difficulty, I guess it's not going done anytime soon). I am willing to spend up to 1000 USD, probably going to look for used parts as well. I think I currently pay 0.28 USD/kWh, don't know if this expensive though.

If you have an up-to-date guide on hardware, and I was too ignorant to find it, please point in its direction. Also, I'd like to have it really powerful, not just 300 Mhash/s or something, more like 2-3 Ghash/s. Whatever is possible with the circumstances I described.

Thank you for your quick replies! I think I will give it a try. The $0.28/kWh are just estimated, as I honestly don't know what I (will pay). I should probably ask for a bill from my landlord (what a strange word).

Will those two 5970's have to be from the same vendor (for cross-fire)? It seems hard to find two cheap, used units from the same vendor.

One general question, if you don't mind: I also read in some other threads about using USB flashdrives for those rigs. Are they used instead of a hdd? Or are they used to store the wallet? If used for both, isn't it very risky to use them, as they have limited reading/writing capabilities (hence data loss after using it for a while).

I think FPGAs are not what I search, the GPUs may still be sold to other miners/gamers or used for rendering. And imho the costs for getting a decent Mhash/s rate on FPGAs seems pretty unrealistic.

Another question, just happened: I received a payment to my local wallet for mining, but in my Bitcoin wallet the address disappeared. I think it's not supposed to disappear, is it? I should be able to receive unlimited transactions on one address. What happened? nvm, I got it all wrong.

Wallet:You don't need a wallet to mine unless you are solo mining which is just stupid w/ only a 5970. I have 16 5970s and don't solo mine. Usb stick is used instead of HDD to reduce power consumption and cost. Good linux distros like BAMT minimize read & writes but even if you do eventually kill one you pay $5 for a new one and keep going. How many $5 usb drives would you need to kill before it costs more than a $80 HDD?

Power:Unless you enjoy taking money putting it into a pile and lighting it onto fire you need to find out our exact electrical rate including all taxes & fees. (total power ) / (total cost). <$0.08 per kWh is golden. <$0.10 per kWh is decent. >$0.10 is going to be tough and likely you will have periods of negative return (paying money to lose money). >$0.20 at this point is just stupid (unless you enjoy losing money).

Crossfire:5970s don't need to be same vendor to crossfire although crossfire isn't used for mining. Each GPU works independently.

You're probably right, but leaving the Bitcoins at the pool didn't seem that bright either. I'm new to this, so I actually did what anyone would do: Leave it at default settings, automatic transfer of > 0.01 BCs.

It is very unlikely the costs will be lower than $0.20. I live in Germany, enough said.

I'll check the prices and then reconsider the investment. I'd be so sad if it didn't work out. Maybe if all you guys quit mining, the difficulty would go down far enough for me to make profit? GO!

I'll check the prices and then reconsider the investment. I'd be so sad if it didn't work out. Maybe if all you guys quit mining, the difficulty would go down far enough for me to make profit? GO!

At which point the profit would bring in enough new (or previously idle) miners to raise difficulty right back up. If you are the marginal miner then you are always the marginal miner. Last in and first one forced out.

It doesn't mean you can't mine it just means be smart about it. The higher your electrical costs the more the higher cost but higher efficiency of FPGA makes sense. An FPGA miner is almost guaranteed to be the most efficient miner so while profits may be lower you have much lower risk of every being forced to quit.

I just recently got into mining as well. I bought 3 x Radeon 6950's on Craigslist for $450 and with an additional $450 in hardware I have a machine mining at 1050 Mhash/sec consuming 470w of power. It was enough to get me going and while it will be a while until any profit comes out of the machine, it's still fun to participate.

I would recommend checking your power rates before making any decisions. The rate you mentioned is very high. I pay $0.105/KWh...that includes electricity, delivery costs, taxes and anything else that may get added on.

But according to the wiki, the FPGA hardware is so expensive, that I could barely make it to 200 Mhashes/s with my budget. So it would be smarter to just let my desktop PC do the job, with ~150MHashes/s (I tweaked it a bit). My computer runs 24/7 anyways, so the power consumption might be slightly higher, but yeah. It actually could pay the higher energy costs and maybe make a little extra, given the fact I didn't pay anything for it (in terms of mining, I bought it for personal use, so no break even to reach).

The second issue with FPGA is: It's really not usable for anything else but mining (at least for me). If the difficulty goes further up, making it impossible to mine (in terms of sanity), I'd have an expensive brick. On the other hand I could still sell those Radeons on eBay.

But according to the wiki, the FPGA hardware is so expensive, that I could barely make it to 200 Mhashes/s with my budget. So it would be smarter to just let my desktop PC do the job, with ~150MHashes/s (I tweaked it a bit). My computer runs 24/7 anyways, so the power consumption might be slightly higher, but yeah.

I think your underestimate how much power GPU use relative to how little 150 MH/s returns. You have one of the worst electrical rates combined with one of the most inefficient cards.

A little exercise:A) find out how many BTC you will earn per month @ 150 MH/s.I will earn ___________

Thank you, I will calculate that when I got my bill. In the meantime I checked various prices and it seems I can't get any offer lower than 0.20 USD per kWh. Assuming 0.28 USD per kWh (which is more likely) I would definitely loose money by mining (right now).

There are alternatives to offset your power cost.I'm not sure about wherever you are, but i know here (Australia) there is a government incentive scheme to move towards solar power, and you can sell your excess back to the energy co.My parents have spent some time/money setting up a solar system and I'm about |--| this close to getting them to house my rig.

Awesome rig can mean a lot of different things...Here electricity is ok (not great, just ok) so getting a decent mhash rig to run at optimal power efficiency is the goal.

things you should do:under clock the memory on the cards.find ways to get discounted or free energy.find ways to use your wasted energy for the power of good (i.e. if you live in a cold climate pump cold filtered air in from an open window through a large heatsink for a liquid cooling system, to heat your house during winter. in summer this system could be reversed, force air out your window through the heatsink)

Meanwhile I realized, that I could just swap my GTX 580 with a new AMD 7970 and easily make .5 Bitcoins a day, even if I would have the worst possible electricity prices. That way my desktop PC (which is running 24/7 anyways) would generate a little money, and the card would do just as good for gaming. Downside would be the crappy Linux drivers from AMD. I know there is progress, blabla, takes too long.

And after I know the exact prices, I will look into getting those 5970s and build a rig (after all calculation is done).

BTW, 250W seems to be the idle power consumption of the GTX 580. They state a stunning 350W under heavy load. The same goes for the 7970...

Thank you also for the suggestion with with solar power. Indeed there is a similar thing going on in Germany. I believe it's running out anytime soon, so Solar Power companies are having a harsh time over here. I don't have any option to make use of this, even though it's common practice over here.

Regarding the heat: I currently am more than happy to use my PC as alternative heating source, as the pipes that transfer the water in the heating seem to be insulated really bad. That way the produced heat is not just waste, but a welcome side-effect to keep my room at a comfortable temperature. I think I won't like this in summer though...

But if you decide to indulge, you can make a 1.2-1.5 Ghash rig easily.

Stalk ebay and other sites and get a hold of two 5970's (4 gpu's)

That's ~$800, then buy an amd sempron and unlock it to an athlon x2 ($40)

Any mobo with two pcie slots will do (~$60)

cheap stick of ramcheap hdd/flashdrive

Rest is for you to spend on a powersupply.

There is absolutely no reason to unlock the sempron. Just gonna use more power that you do NOT need from a CPU.

You can get four brand new 5850s for cheaper than two 5970, which go a lot faster... and a motherboard that can hold 4 cards for around 60 bucks as well. Just need PCIe 1x riser cables to 16x. 7 bucks.

Single rail at least bronze rated PSU and at least 900w. You are fine with that. 80-100 bucks. Depending on brand. PSU is the MOST important piece of your rig. Don't go cheap.

And .28 bro damn... that is gonna cost you about 120 bucks per rig with 4 cards. You probably wont even come close to breaking even.

Meanwhile I realized, that I could just swap my GTX 580 with a new AMD 7970 and easily make .5 Bitcoins a day, even if I would have the worst possible electricity prices. That way my desktop PC (which is running 24/7 anyways) would generate a little money, and the card would do just as good for gaming. Downside would be the crappy Linux drivers from AMD. I know there is progress, blabla, takes too long.

And after I know the exact prices, I will look into getting those 5970s and build a rig (after all calculation is done).

BTW, 250W seems to be the idle power consumption of the GTX 580. They state a stunning 350W under heavy load. The same goes for the 7970...

Thank you also for the suggestion with with solar power. Indeed there is a similar thing going on in Germany. I believe it's running out anytime soon, so Solar Power companies are having a harsh time over here. I don't have any option to make use of this, even though it's common practice over here.

Regarding the heat: I currently am more than happy to use my PC as alternative heating source, as the pipes that transfer the water in the heating seem to be insulated really bad. That way the produced heat is not just waste, but a welcome side-effect to keep my room at a comfortable temperature. I think I won't like this in summer though...

Solar power is not cheaper. I looked in to it and the cost for enough wattage from a solar power unit is WAY too expensive. The best way by far is just your regular power source.

Also man, you need to understand that the bitcoin calculators are ABSOLUTE BEST CASE SCENARIO for the BTC per day output and what hash power you have. You would be wise to cut that estimation in half, then go from there. And consider anything over that is a bonus.

Thanks for your reply. I am not sure about those four 5850s being cheaper than two 5970. They seem to be pretty equal, at least here in Germany (used ones of course). Do you mean 120 bucks for the power per month?

Regarding the 7970, I don't understand why you'd say it would not work. Sure, I did use the calculator, but as I would sell my old GTX 580, I would not spend more than $200 extra. IF I calculated them in, the break even would be in about a year. But as I need this card (or any other high-end card) anyways, I would just not calculate it in. That way I would make profit, even though it's not much. Best case 0.5 BTC per day, according to you at least 0.25 BTC per day (using the .28 USD).

Regarding the rig: Let's first see what I actually have to pay per kWh. I'll keep you posted.

I have one general question regarding my desktop system. I realized the 7970 is a brand new GPU from AMD, and there are only a few cards different from the reference design. I would not have a problem with that, but would those of you who have more experience recommend waiting for other/better models to come out? The reference design already features the cooling system of my choice (blowing out of the case), so I don't know what else could be improved in later versions. Sorry for this being slightly off-topic, I'm still waiting for my actual $/kWh and meanwhile would like to make my desktop profitable. Thank you!